The implementation of WLANs in wireless communication systems has expanded dramatically to replace wired computer networks. Using a WLAN, an end user may gain benefits such as flexibility and freedom of movement. The WLANs provide faster bit rates and are cheaper because they operate on an unlicensed band. Additionally, the current WLAN architecture lacks the ability and mechanisms to page the WTRU to ensure its presence for the delivery of Internet-based services.
Existing 3GPP UMTS systems provide WTRU users with access to Internet-based services such as MMS. MMS is a store-and-forward method of transmitting graphics, video clips, sound files and short text messages, (i.e., emails), over wireless networks. It is desirable to implement a wireless communication system which provides 3GPP-based services using a WLAN interworking with a 3GPP system.